首页
登录
职称英语
A new kind of radar has been developed for spaceship travelers. A working la
A new kind of radar has been developed for spaceship travelers. A working la
游客
2025-07-24
31
管理
问题
A new kind of radar has been developed for spaceship travelers. A working laboratory model of a new system of radar that makes use of a beam of light is said to be ten thousand times more accurate than the best comparable system of radar that uses microwaves.
The model has shown that this radar system, known as laser-doppler radar, can measure with absolute precision speeds varying from spaceship orbital injection(进入) velocities (速度)of five miles per second down to virtual stops—speeds of less than one ten-thousandth of an inch per second. According to the scientists who are developing this system, such fine measures of velocity are of prime importance in space missions. In a rendezvous (对待) between two spaceships, or in a landing approach by a vehicle onto an orbiting space station, a bump could rip open a ship’s skin, or a nudge could knock the station out of its orbit.
The light-beam radar, which operates at a frequency of trillions of cycles(百万兆)per second, could easily detect and measure the movement of vehicles edging up to a satellite space station. A control system using so precise a signal as this would allow a huge vehicle to dock at a space station as lightly as a feather. [br] It is implied but not stated in the passage that______.
选项
A、Laser-doppler radar is more accurate than microwave radar
B、Microwave radar may not ensure absolute precision in measuring varying speeds
C、The light-beam radar can measure only slow speeds with accuracy
D、Microwave radar operates at a higher frequency than laser-doppler radar
答案
B
解析
根据第一段第二句对第二段第一句可推断B为正确。A项已在文中明确提出过,C和D项与原文相反。
转载请注明原文地址:https://tihaiku.com/zcyy/4174019.html
相关试题推荐
FromMondayuntilFridaymostpeoplearebusyworkingorstudying,butinth
WhichofthefollowingisNOTincludedinthewriter’sworkingexperience?[br]
Afterworkingforthewholemorning,weweregladtotake______rest.A、fewminut
【S1】[br]【S6】developed
You______betired,foryou’veonlybeenworkingforanhour.A、mustnotB、won’t
【B1】[br]【B5】A、completeB、workingC、fitD、poorC
TheAmericantypeoffootballwasdevelopedinthe19acenturyfromsoccera
【B1】[br]【B2】A、playingB、studyingC、livingD、workingD原文中说的是一群建筑工人在工作,所以小孩在观看建筑
Hefailedtheexam,______provedthathehadn’tbeenworkinghardenough.A、that
【B1】[br]【B2】A、talkingB、workingC、meetingD、studyingCtalk(说话)是不及物动词,不能直接跟宾语;w
随机试题
在进行外汇期货交易时,交易者应该明确标准化合约的基本要素,这些基本要素包括()。A、合约指向的外汇币种B、每份合约的面值C、合约的交割月份,以及合
圆水准器通过调节基座上的脚螺旋使圆水准器气泡居中,达到光轴初平的目的。
当水体受到污染时,通过下列哪项指标的测定可判断其污染可能来源于生活污水?()
(2013年)根据《行政强制法》的规定,行政机关应当及时作出解除查封、扣押决定的
根据《中国公民出国旅游管理办法》规定,组团社经营出国旅游业务,应当与旅游者订立书
下列说法正确的是: A.2016年第一季度,全国星级饭店餐饮总收入为248
关于城镇道路土路基雨期施工的说法,正确的是()。A、集中力量,全面开花,快速施
Thechangeinthatvillagewasmiraculou
17314
以下属于结账业务的是()。A.将本期实现的各项收入转入“本年利润”账户 B.用
最新回复
(
0
)